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Ryerson University
GEO 131
David Atkinson

GEO 131- ENVIRONMENT SCIENCE TEXTBOOK NOTES CHAPTER 1 - ECOSYSTEMS AND HUMANS Environmental Science - Is concerned with the rapidly increasing human population, the use and abuse of resources, damage caused by pollution and disturbance, and the endangerment and extinction of species and natural ecosystems - Ecology -> The study of the interrelationships of organisms and their environment - Geography -> The study of the natural features of earths surface, including climate, topography, soil, and vegetation, as well as intersections with the human economy - Environmental Ecology: The ecological effects of pollution and disturbance - Ecologists: Are the specialists who study relationships among organisms and their environment - Environmental scientists: generalists who use science-related knowledge relevant t environmental quality; air or water chemistry, climate modeling, or ecological effects of pollution - Environmentalists: involved in environmental issues Earth, Life, and Ecosystems Earth - Closest 3rd planet to the sun, orbiting that medium-sized star energy every 365 days - About 70% of its surface is covered with liquid water & remaining is terrestrial area of exposed land & rocks (vegetation) - Beginning of life occurred 3.5 billion years ago - Genesis happened naturally, as a direct result of appropriate physical and chemical conditions - Only place in the universe known to sustain life and its associated ecological processes - We can consider the universe at various hierarchical levels -> scale ranges: extremely small: subatomic particles & photons to LARGE: galaxies & the universe - The realm of ecology encompasses the following levels: 1. Individual organisms: living things (genetically and physically discrete), 2. Populations: species occur together in time and space, 3. Communities/populations of various species (same as population), 4. Landscapes/seascapes: Spatial integrations of various communities over larger areas, 5. The entire biosphere Species & Ecosystems - Biosphere can be viewed as a single ecosystem - Ecological interpretations of the natural world consider the diverse, web-like interconnections among the many components of the ecosystems in a holistic manner - All species are sustained by environmental resources: the “good and services” provided by ecosystems - All organisms require specific necessities of life, such as inorganic nutrients, food, and habitat with particular biological and physical qualities - The development and growth of individual people, their populations, and their societies & cultures are limited to some degree by environmental factors - EXAMPLE: cold or dry climatic conditions, inhospitable terrain, and other factors that influence food production by agricultural/hunting - Humans are labelled as “homo-sapiens” (SCIENTIFIC TERM) Latin for “WISE-MAN” - Humans are not the only species that can cope with ecological constraints in clever ways - Although other species have developed behavioral changes that allow more efficient exploitation of their environment - unfortunately, humans also have an unparalleled ability to degrade resources and ecosystems and to cause the extinction of other species Environmental Quality - Deals with anthropogenic pollution and disturbance and the effects of these on humans, their economies, other species, and natural ecosystems - Pollution can be caused by everything in the atmosphere Environmental Impacts Of Humans - The cumulative impact of humans on the biosphere is a function of two factors: The size of the population and the per capita environmental impact - IMPACT FORMULA: I=PxAxT - I= total environment impact of population - P= population size - A= estimate per capita affluence of resource use - T= degree of technological development of the economy - Calculations based on this PAT formula clearly show that affluent, technological societies have a much larger per capita environmental impact than do poorer ones - Energy use is a helpful indicator because it is required in virtually all activities in a modern society EXAMPLE: driving, heating, etc. Ecologically Sustainable Development - Development of an economic system that uses natural resources in ways that do not deplete them - Present human economy is clearly non-sustainable - Economic growth: Increases in the size of an economy because of expansions of both population and per capita resource use - Development refers to categorization of countries to reflect the status of their economy - Developed countries are also known as high-income countries - Less-developed/low-income countries -> have much less economic infrastructure and low per capita earnings - Rapidly developing/middle-income include china, malaysia, brazil, chile - Economic development is different than economic growth - A sustainable economy must be fundamentally supported by the wise use of renewable resources that are not used more quickly than their rate of renewable - If a sustainable human economy is not attained, then the non-sustainable one will run short of resources and could collapse - In ecologically sustainable development, countries develop without depleting their essential base of natural resources, basing their development on the wise use of renewable sources of energy and materials CHAPTER 3 - THE PHYSICAL WORLD Planet Earth - The universe is thought to have originated as many as 12-15 billion years ago during an immense cataclysm known as the “BIG BANG” - All the mass of the universe consisted of the two lightest elements, HYDROGEN & HELIUM - which existed as an extremely diffuse gaseous mass. Eventually under the influence of gravity the hydrogen and helium aggregated and became compressed under enormously high pressure and temperature into developing stars. This caused the formation of heavier elements through nuclear fusion, accompanied by the release of tremendous amounts of energy. - SOLAR SYSTEM: the sun, its orbiting planets, miscellaneous comets, meteors, asteroids, and other local materials - The age of the solar system is 4.6 billion years - Earth is a dense planet, as are other so-called terrestrial planets located relatively close to the sun: mercury, venus, and mars - the mass of these planets consists almost entirely of heavier elements such as iron, nickel, magnesium, aluminum, and silicon = these inner planets were formed by a selective condensing of heavier elements out of the primordial planetary nebula - Earth’s sphere is thought to be composed of four layers -- the core, mantle, lithosphere, and crust - The internal heat of Earth is generated by the slow, radioactive decay of unstable isotopes of elements such as uranium - The mantle is a less dense region enclosing the core = thick and composed of minerals in a plastic, semi-liquid state known as magma - The mantle contains large amounts of relatively light elements, notably silicon, oxygen, and magnesium, occurring as various mineral compounds - Lithosphere= thick and made of rigid, relatively light rocks - Igneous rocks include basalt and granite, which are formed by the cooling of molten magma - the mineral forms depend on the rate of cooling and other factors. - Sedimentary Rocks = limestone, dolomite, shale, sandstone, and conglomerates - Metamorphic Rocks = formed from igneous or sedimentary ones that were changed under the combined influences of geological heat and pressure Geological Dynamics - Earth has been subject to enormous geological forces that have greatly affected its mineralogical composition and surface features - The predominant influences are tectonic forces - which are associated with crustal movements and other processes that cause structural deformation of rocks and minerals - Earthquakes and volcanoes are also tectonic phenomena, influencing earth’s crust and surface with extremely powerful, sometimes disastrous events - Other massive geological forces include rare, cataclysm strikes into our planet by meteorites and extensive glaciation associated with climatic cooling. METEORITES - Earth is frequently struck by fast-moving rocky or metallic objects from space known as meteorites - Very large meteorites are extremely rare but they can cause enormous damage - Immense sea waves can also be caused by a meteorite impact Plate Tectonics - The theory of plate tectonics concerns the dynamics of Earth’s crustal materials. - In simple terms, this theory suggests that Earth’s crust and mantle behave as an enormous convecting system - This is characterized by slow surface movements into the upper zone of the mantle - New crust forms where there is an upwelling of magma from the upper mantle. - The magma rises to the surface, solidifies, and then extends laterally in a process known as sea-floor spreading - In other zones, there is a compensating subduction of sea-floor crust back down into the mantle, where it is re-melted and convected laterally. - An earth quake is a trembling or movement of the earth caused by a sudden release of geological stresses at some point within the crust or upper mantle. - Earth quakes are most often caused when crustal plates slip across or beneath each other at their faults. Earthquakes can also be caused by a volcanic explosion. Although their seismic energy can affect a large area, earth quakes have a spatial focus known as the epicentre and defined as the surface position lying above the deep point of energy release. - Undersea earthquakes can trigger a fast-moving sea surface phenomenon known as a tsunami or seismic sea wave. - A tsunami is barely noticeable at sea, but it can become gigantic when the wave reaches shallow water and piles up to heights that can swamp coastal villages and towns - Volcanoes are vents in the Earth’s surface that spew molten lava onto the ground and eject liquid, solid, and gaseous materials into the atmosphere. - The largest volcanic eruptions can literally explode mountains, ejecting immense quantities of material into the environment and causing enormous damage and loss of life GLACIATION - Glaciers - or persistent sheets of ice are common features in high-latitude environments of the Arctic and Antarctic - Glaciers can also occur at high altitude on mountains, even in tropical countries such as New Guinea. - Glaciers are formed from deep, persistent snowpacks, which become compressed into ice as their weight accumulates - Most glaciers occur on land, but some extend onto the ocean - about 10% of the land surface of Earth is covered with glac
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